package com.hmdp.service.impl;

import com.hmdp.dto.Result;
import com.hmdp.entity.SeckillVoucher;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.SimpleRedisLock;
import com.hmdp.utils.UserHolder;
import org.springframework.aop.framework.AopContext;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.util.Collections;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {
    @Autowired
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private ISeckillVoucherService seckillVoucherService;
    private RedisIdWorker redisIdWorker;
    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;
    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }
    @Override
    public Result seckillVoucher(Long voucherId) {
        //获取用户
        Long userId = UserHolder.getUser().getId();
        //1.执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(), userId.toString()
        );
        //2.判断结果是否为0
        int r = result.intValue();
        if (r != 0){
            //2.1不为0，代表没有购买资格
            return Result.fail(r == 1?"库存不足":"不能重复下单");
        }


        //2.1为0，有购买资格，把下单信息保存到阻塞队列
        //TODO
        //3.返回订单id
        Long orderId = redisIdWorker.nextId("order");
        return Result.ok(orderId);
    }
    /*//1.根据id查询优惠券
        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
        //2.判断秒杀是否开始和结束
        if (voucher.getBeginTime().isAfter(LocalDateTime.now())) {
            return Result.fail("秒杀尚未开始");
        }
        if (voucher.getEndTime().isBefore(LocalDateTime.now())) {
            return Result.fail("秒杀已结束");
        }
        //3.判断库存是否充足
        if (voucher.getStock() < 1) {
            return Result.fail("库存不足");
        }
        Long userId = UserHolder.getUser().getId();
        //创建锁对象
        SimpleRedisLock lock = new SimpleRedisLock("order" + userId, stringRedisTemplate);
        //获取锁
        boolean islock = lock.tryLock(5);
        //判断是否获取锁成功
        if (!islock){//获取失败，返回错误
            return Result.fail("一人只能下一单");
        }

        try {
            //获取代理对象（事务）
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            return proxy.createVocherOrder(voucherId);
        } finally {
            //释放锁
            lock.unlock();
        }*/
@Transactional
    public Result createVocherOrder(Long voucherId) {
        //一人一单
        Long userId = UserHolder.getUser().getId();
        Integer count = query().eq("user_id", userId).eq("voucher_id", voucherId).count();
        if (count > 0){
            return Result.fail("用户已经购买过一次了");
        }
        //4.扣减库存
        boolean success = seckillVoucherService.update()
                .setSql("stock = stock - 1")
                .eq("voucher_id", voucherId).gt("stock",0)
                .update();
        if (!success){
            return Result.fail("库存不足");
        }
        //5.创建订单
        VoucherOrder voucherOrder = new VoucherOrder();
        //5.1设置订单id
        Long orderId = redisIdWorker.nextId("orderId");
        voucherOrder.setId(orderId);
        //5.2设置用户id
        voucherOrder.setUserId(userId);
        //5.3设置优惠券id
        voucherOrder.setVoucherId(voucherId);
        //5.4保存到数据库
        save(voucherOrder);
        //6.返回订单id
        return Result.ok(voucherId);
    }
}
